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Complex regional pain syndrome O CRPS is a highly painful, limb-confined condition, which arises usually after trauma. O Associated with a particularly poor quality of life, and large health-care and societal costs. O Crossroads of interests of several disciplines including rheumatology, pain medicine, neurology, physiatry.

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Clinical presentation of CRPS Early CRPS of the right hand: Clearly visible signs include swelling, red color and a shiny skin. As the disease progresses some of these visible signs can partially or completely disappear while pain may persist unabated.

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Patients with CRPS can present in many different ways……. O Limbs can be hot or cold, shiny, swollen or thin, red or blue with scaling or clammy skin. O Some patients cannot tolerate slight air movement on their skin, while others have completely lost the ability to feel any stimulus to the limb (with normal nerve conduction studies). O Blister formation, skin ulcerations, severe atrophy, joint ankylosis, dystonia and myoclonus may also be present. O Joints usually feel stiff with reduced range and weakness; often limb parts cannot be moved at all, and there is a fine tremor.

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O The IASP has proposed dividing CRPS into two types based on the presence of nerve lesion following the injury: O CRPS type I (reflex sympathetic dystrophy). Minor injuries or fracture of a limb precede the onset of symptoms. O CRPS type II (causalgia) develops after injury to a major peripheral nerve.

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O CRPS diagnosis is based upon clinical criteria and that there is so far no gold standard nor any objective diagnostic tool. O It is a diagnosis of exclusion. O Budapest Criteria used for diagnosis

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PAIN Burning coldness Crushing, Numb and hot Help me someone, Make it stop! It started out so innocently When I fell off my bike My foot began with a twinge Then relentlessly, Crept up my limb It became unbearable Moments passed like years Looking for a miracle A never-ending nightmare Guillotines, power saws Alligators and lion's jaws Nightmares of horror Terrified to close my eyes Fearing more awaits inside Branded by the endless pain Am I going to go insane? You don't know just how I feel Does that mean it isn't real? Is my world just not true? Don't I see and feel -- like you? Please don't stop trying I can't help my crying I feel so maimed Help me, Help me I'm in pain!

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O The primary action of tDCS for pain reduction is direct modulation of activity in certain areas of the brain that are involved in pain processing, such as the thalamus and inhibitory corticospinal mechanisms. O tDCS is used in other pain syndromes, such as fibromyalgia, phantom pain and central pain in traumatic spinal cord injury.

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Objectives Our proposed study has 2 specific aims: Determine the effect of tDCS on pain and quality of life associated with CRPS. Determine the specificity of tDCS site for modulation of pain and quality of life associated with CRPS.

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Study Design O Double-blind, randomized, placebo-controlled study O Subjects stratified based on pain intensity and duration of CRPS. O Subjects then randomly assigned to 1 of the following 3 groups: Group 1: anodal tDCS over DLPFC Group 2: anodal tDCS over M1 Group 3: sham tDCS over DLPFC

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Study Population Inclusion criteria: Subjects must be at least 18 years of age with diagnosed CRPS following the recently updated Budapest criteria Exclusion criteria: Within 1 month of recruitment, addition or change in the dosage of drugs known to interfere with pain Untreated depression History of head injury with loss of consciousness, severe alcohol or drug abuse, or psychiatric illness, Seizure disorder Pregnancy Presence of ferromagnetic material in the cranium except in the mouth, including metal fragments from occupational exposure, and surgical clips in or near the brain.

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Intervention One 35 cm 2 saline-soaked sponge electrodes placed over the scalp sites overlying the relevant cortex and reference electrode placed supraorbitally. Battery-operated direct current stimulator for delivery of stimulation (Magstim Ltd., Wales, UK). With the exception of the control group, each subject will receive 20 minutes of tDCS at an intensity of 1.4mA. (These values result in a current density of 0.04mA/cm 2 and a charge density of 480 Coulombs/M 2 ) For the control condition, stimulation intensity will be ramped up then ramped down over a 30-second window.

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Assessment O Short-Form McGill Pain Questionnaire, which will serve as the primary behavioral outcome for this study. O The SF-36 Health Survey will be used to measure changes in quality of life.